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14 January 2016
Study finds high melt rates on Antarctica’s most stable ice shelf
A new study measured a melting rate that is 25 times higher than expected on one part of the Ross Ice Shelf. The study suggests that high, localized melt rates such as this one on Antarctica’s largest and most stable ice shelf are normal and keep Antarctica’s ice sheets in balance.
Data Management Isn’t Optional; It’s Essential to Being Successful
This is part of a new series of posts that highlight the importance of Earth and space science data and its contributions to society. Posts in this series showcase data facilities and data scientists; explain how Earth and space science data is collected, managed and used; explore what this data tells us about the planet; and delve into the challenges and issues involved in managing and using data. This series is intended to demystify Earth and space science data, and share how this data shapes our understanding of the world.
13 January 2016
Ocean circulation changes may have killed cold-water corals
Successive and abrupt changes in North Atlantic ocean circulation over the past 4,500 years seem to have caused major reductions in some cold-water coral ecosystems, finds a study published in Geophysical Research Letters, a journal of the American Geophysical Union.
The new study shows changes in sea surface circulation over the last few thousand years were more sudden than previously thought and in some cases led to abrupt collapses of cold-water coral ecosystems. The researchers found the first evidence that perturbations in the Atlantic Meridional Overturning Circulation (AMOC) led to cold-water coral ecosystems decline from 100 to 1,200 years ago.
Underwater volcanoes may have sent carbon dioxide to the atmosphere at the end of the last ice age
During the last glacial period, Earth’s land and sea stored carbon as both dissolved carbon dioxide and biomass. But as the ice receded, water warmed and organisms decayed, that carbon surged into the atmosphere. Most of the released gas came from the atmosphere originally, but in a new study, a data anomaly hints that a small percentage of it came from volcanoes erupting on the ocean floor.
21 December 2015
Climate change and bark beetles spell doom for Rocky Mountain spruce forests
The combination of climate change and spruce bark beetles could drastically alter Rocky Mountain spruce and pine tree populations over the next three centuries, according to a new study. Using an improved model of forest growth, death, and regeneration, a group of scientists predicts that spruce populations will decline and lodgepole pines will take their place.
According to new research presented at the 2015 American Geophysical Union Fall Meeting, the demographics of a forested region can be dramatically affected by insect outbreaks and fires over time. In addition, different kinds of trees have different tolerance to drought, strong winds and temperature changes. “These act to create competition between individual species and even between trees,” said Adrianna Foster, an environmental scientist at the University of Virginia and lead author of the new study.
17 December 2015
Preserved trees that grew 12,000 years ago improve radiocarbon dating calibrations
Scientists use radiocarbon dating to determine the age of everything from bone and teeth to seeds and straw. The accuracy and precision of those dates depends on careful calibration. New data from logs unearthed in a small floodplain in New York’s Lake Ontario lowlands will allow scientists to refine the calibrations for a 1,200 year period that occurred about 12,000 years ago, according to Carol Griggs, a dendrochronologist at Cornell University in Ithaca, New York.
The record represents “a new independent radiocarbon series for this time period,” Griggs said at the 2015 American Geophysical Union Fall Meeting in San Francisco.
Volcano pressure guns show how rocks spew and eruptions ensue
The vinegar volcano is a stale science experiment. But Italian geologist Valeria Cigala takes the tired demonstration to a violent new level…
15 December 2015
One Million Icequakes
Nestled in the Arctic is a glacier like no other. This glacier quakes once a minute creating seismic events that rattle the earth—more frequently than scientists have ever seen. Understanding why these icequakes are so common may help researchers predict future ice flow, a process that propels climate-driven sea level rise.
4 December 2015
Dinosaur-killing asteroid may have caused global algal bloom, marine extinction
The asteroid impact suspected of killing the dinosaurs may also have triggered a global algal bloom that contributed to a massive marine extinction more than 60 million years ago, according to a new study published in the Journal of Geophysical Research: Planets, a publication of the American Geophysical Union.
Around 66 million years ago, an asteroid 10 kilometers (six miles) in diameter slammed into the Yucatan peninsula, creating a crater 180 kilometers (110 miles) across and 20 kilometers (12 miles) deep. The Chicxulub impact sent tiny spheres of material up into the atmosphere where they became super-heated. Approximately 1023 of these microscopic spherules were ejected and re-entered the atmosphere to create a global carpet of silica glass 3-millimeters (0.19-inches) thick, known geologically as the Cretaceous-Paleogene layer.
2 December 2015
Hydrothermal Hunt: How to recover an Autonomous Underwater Vehicle
The Sentry Autonomous Underwater Vehicle (AUV) can reach depths of 6,000 m (or about 3.73 miles) below sea level. It is one the best tools for detailed mapping of the water column and deep ocean floor. But even if your instrument has survived the crushing hydrostatic pressures at the bottom of the ocean, you will find another kind of pressure waiting back up on deck. Recovering unique and precious scientific equipment out of the swelling ocean and putting it back onto a moving ship is an intimidating prospect. Here AUV Program manager, Carl Kaiser, gives us his key tips for ensuring a smooth AUV recovery and how to cope when things start to go wrong.
GeoSpace is a blog on Earth and space science, managed by AGU’s Public Information staff. The blog features posts by AGU writers and guest contributors on all sorts of relevant science topics, but with a focus on new research and geo and space sciences-related stories that are currently in the news.